This application requests the third renewal of our Chemistry-Biology Interface (CBI) Training Grant. In 1995 we launched a new interdisciplinary training program at the University of Massachusetts that built on existing strengths and harnessed our faculty commitment to collaboration between the physical and life sciences. We successfully implemented a curriculum that complemented the requirements of the participating graduate programs, adding enough training elements to efficiently train students with either chemical or biological backgrounds in the complementary discipline. The subsequent period (2000-2005) was one of tremendous growth of the program: the number of affiliated students grew from 14 to over 60, as students well beyond those with CBI funding recognized the value of the CBI training and community. During the current funding period our CBI Training Program has become a major force on campus, influencing faculty hiring and construction of new buildings and renovations. The CBI Training Faculty has grown from 19 to 27, and continues to provide cross-training to over 60 students from the four participating graduate programs of Chemistry, Molecular & Cellular Biology, Chemical Engineering, and Polymer Science & Engineering. We anticipate continued growth of our CBI Program as additional departments (notably Physics and Computer Science) move into CBI- related areas. The CBI Program currently provides NIH support for 6 pre-doctoral students, and a University match supports 2 additional Traineeships. To continue to foster the growing strength of the CBI program as it expands into new disciplines and trains increasing numbers of students, we request an increase to 8 NIH-funded Traineeships. Notable features of our CBI Program include the participation of the Departments of Chemical Engineering and Polymer Science & Engineering, which enriches CBI training with quantitative, biomaterials, and bioengineering perspectives and projects. Our popular Drug Design course, developed as an integral part of the CBI curriculum, features weekly seminars by speakers from the pharmaceutical industry and a field trip to tour a company. Our CBI retreat has grown into a vibrant annual event that forges connections with researchers at UMass Medical School. Finally, CBI students, in partnership with students of the new UMass Institute for Cellular Engineering, are organizing a new annual Career Day to further enhance their CBI training. Thus the CBI curriculum and community are rich in opportunities for training in the methods and intellectual framework of both chemistry and biology, which prepares our CBI graduates to pose and solve significant biomedical questions in their future work.